HP will start selling the Wi-Fi version of its new TouchPad tablet in the UK from "mid-July" at prices of £399 (16GB) and £479 (32GB), the company said on Thursday.

The device, which has a 9.7-inch screen, the same size as Apple's iPad, runs HP's own webOS operating system inherited from Palm, which HP acquired in mid-2010.

HP's greatest strength is that it is the biggest seller of PCs to corporations, and so wields enormous power in seeking to sell tablets to the same customers. In that it is likely to vie with RIM, maker of the BlackBerry, with its PlayBook device which runs RIM's own QNX operating system.

Meanwhile RIM's 7-inch PlayBook will go on sales from Thursday 16 June, priced at £399 for a 16GB model. It will be sold through Dixons retail stores, Carphone Warehouse, Best Buy, Insight UK and Phones4U.

Apple's iPad 2 costs £399 for a 16GB Wi-Fi version, and £479 for a 32GB version, making the TouchPad exactly price-competitive. A key differentiator though may be how quickly HP can persuade corporate and third-party developers to write applications for its app store.

Another challenge is likely to be persuading phone operators to sell the forthcoming HP Veer, a followup to the unsuccessful Palm Pre, which can act as a companion to the TouchPad. The Guardian understands that European operators have been wary of committing to the Veer after the Pre's disappointing sales performance in 2009.

The TouchPad has a 1.2GHz Qualcomm Snapdragon processor and includes NFC (Near-Field Communications) for interaction with HP smartphones such as the Veer.

Preorders will begin on Sunday 19 June, though the company did not say whether that will be through retailers or its own website. No retail partners were announced.

The tablet - HP's first using webOS - will be available in the US, France and Germany from 1 July. Availability is scheduled for "later this year" in Ireland, Spain, Australia, Hong Kong, New Zealand and Singapore.

HP has previously tried to sell Windows-based tablets, even being featured in speeches by Microsoft chief executive at the keynote speech at the 2010 Consumer Electronics Show in Las Vegas. But it has seen little takeup.

Now, the company plans to put increasing emphasis on the possibility of webOS to differentiate its products from those of other PC manufacturers: Leo Apotheker, the new chief executive, said earlier this year that a growing number of HP PCs will ship with webOS as a layer running alongside Windows.

"What makes HP TouchPad a compelling alternative to competing products is webOS," said Jon Rubinstein, senior vice president and general manager, Palm Global Business Unit, HP. "The platform's unmatched features and flexibility will continue to differentiate HP products from the rest of the market for both personal and professional use. This is only the beginning of what HP's scale can do with webOS."

Rubenstein knows the size of the challenge he is up against: he is the former head of hardware at Apple, and was there when the iPad was being developed, though he left before it was released.

•Motorola shipped 250,000 of its Android Honeycomb-based Xoom tablets in the first quarter of 2011, the company has told the Guardian. The figures indicate the number sent for sale to shops. There are no figures yet on how many have been sold through retail and other channels. Richard Windsor, technology analyst at the brokers Nomura, has estimated that around 100,000 have been sold in the first quarter.

Scott Forstall, Apple's head of iPhone software, said earlier this week that Apple has so far sold 25m iPads - which implies that it has sold around 5.5m already in the first two months of this quarter. That would put this on track to be its best-selling quarter so far, ahead even of the Christmas quarter.